Gas-insulated apparatuses such as gas-insulated switchgears such as GIS, gas-insulated buses, and gas-insulated transformers are generally used in power facilities such as, for example, substations. The gas-insulated apparatus is an apparatus in which high-voltage conductors are housed in hermetic metal containers filled with insulating gas and the high-voltage conductors are supported by insulators. It is known that, when a defective portion with a contact failure, the mixture of metal foreign matter, or the like is generated inside the metal container in this gas-insulated apparatus, a partial discharge occurs from the defective portion.
Leaving the partial discharge in the gas-insulated apparatus as it is soon leads to dielectric breakdown, which has a possibility to develop into the occurrence of a serious accident. Therefore, it is important to prevent the serious accident by discovering the partial discharge at an early stage and taking some measure such as repairing the defective portion.
Here, as a preventive maintenance technique for an insulation diagnosis of a gas-insulated apparatus, there has been proposed a partial discharge monitoring system including: a plurality of partial discharge detecting units which detect a partial discharge inside the gas-insulated apparatus; and a data processing device which monitors partial discharge signals from the respective partial discharge detecting units via a ring network.
In the case of the conventional partial discharge monitoring system and partial discharge monitoring method, since the partial discharge signals from the respective partial discharge detecting units are constantly sent to the network, a load is given to the network, and a continuous increase of data may cause a trouble in the communication of the network.